Frame gasket for fuel cell and method of molding the same

ABSTRACT

A frame gasket may include a flat base, which is positioned along the edge of stack constitutional parts and which includes a first elastic base and reinforced fibers mixed therein to ensure sealing of a fuel cell stack, and first projection units, which project over the base and which include a second elastic base.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2016-0060449, filed May 17, 2016, the entire content of which isincorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a self-standing frame gasket for a fuelcell, which enables an elastomer to have sufficient rigidity andimproves sealing and durability even though an insert is not applied,and a method of molding the same.

Description of Related Art

A polymer electrolyte membrane fuel cell (PEMFC) is extensively appliedas a fuel cell for vehicles. A gasket must be generally used for eachcell in order to maintain a seal against hydrogen, which is a reactiongas, air, and coolant in a fuel cell stack for use in vehicles.

The gasket used in the stack for fuel cell vehicles must satisfy all ofvarious requirements such as appropriate hardness, excellent elasticity,very low compression set, excellent mechanical properties, excellentacid/hydrolysis resistance, low diffusivity of hydrogen/air/coolant, lowcontent of impurities causative of catalytic poisoning, excellent heatresistance, high electric insulation, excellent productivity, and lowcost.

Typical elastomers that sufficiently satisfy the aforementionedrequirements and are frequently used in gaskets for fuel cell stacks maybe broadly classified into fluorine, silicone, and hydrocarbon-basedelastomers.

The fluorine-based elastomer is broadly classified into FKM and FFKM,and has been extensively applied for various purposes, such as in thevehicle/construction/petrochemical industries, in recent years.Particularly, the fluorine-based elastomer has been considered to beusable over a long period of time under severe driving conditions of thefuel cell vehicle due to excellent elasticity, acid resistance, and heatresistance, thus receiving a lot of attention as the gasket for the fuelcell stack. However, there are drawbacks of poor injection moldabilityand cold resistance and high prices.

The silicone-based elastomer is broadly classified into a generalsilicone elastomer, such as polydimethylsiloxane, and reformed silicone,such as fluorinated silicone. In the case of the silicone-basedelastomer, liquid-phase silicone rubber may be more frequently used thansolid-phase silicone rubber during fine injection molding, therebyensuring excellent injection moldability. However, there is a drawbackin that a silicone impurity is eluted under the driving condition of thefuel cell, thus poisoning a platinum catalyst in the electrodes.

Further, an elastomer, such as an ethylene propylene diene monomer(EPDM), an ethylene propylene rubber (EPR), an isoprene rubber (IR), andan isobutylene-isoprene rubber (IIR), is frequently used as thehydrocarbon-based elastomer. Generally, the hydrocarbon-based elastomerhas merits of excellent cold resistance and low prices, but has adrawback in that it is difficult to use the hydrocarbon-based elastomerover a long period of time because the physical properties aresignificantly reduced at a high temperature of 100° C. or higher.

Further, in the conventional technology, the gasket for the fuel cellmay be integrated with a metal separator, a gas diffusion layer, amembrane electrode assembly, or a resin frame as an insert, or a polymerfilm may be layered on or attached to one side of the gasket so that thegasket, which has insufficient rigidity, is supported. As for theconventional technology, the necessity of a process for integrating thegasket and the insert, applied to each cell of the fuel cell stackincluding hundreds of cells layered thereon, and a process for using anadditional film and attaching a film and a gasket, defects (deformationand surface contamination of the separator) during the integrationprocess, and the cost of quality inspection after integration serve toincrease the production cost and to reduce the productivity of the fuelcell stack.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing aframe gasket for a fuel cell, which maintains its shape even when aninsert is used by increasing the rigidity of the gasket including anelastomer, and a method of molding the same. Accordingly, an unnecessaryprocess for applying an insert to a mold during injection molding of thegasket may be obviated, and the sealing, durability, productivity, andmarketability of the fuel cell may be improved.

To accomplish the above object, various aspects of the present inventionare directed to providing a frame gasket for a fuel cell, the framegasket including a base, which is positioned along an edge of aseparator, a membrane electrode assembly, or an end plate to extend froman edge of the separator, the membrane electrode assembly, or the endplate to a predetermined width and height, and which includes a firstelastic base and reinforced fibers mixed therein to ensure sealing of afuel cell stack, and first projection units, which extend from an upperend of the base to project over the base and which include an elastomer.

The first projection units may extend from the upper end of the base,and the base and the first projection units may extend along the edge ofthe separator, the membrane electrode assembly, or the end plate to forma closed loop.

The first projection units may include a material including a secondelastic base.

The first elastic base may be the same as the second elastic base, andthe base and the first projection units may be integrally molded.

The first projection units may include a material including a secondelastic base and the reinforced fibers mixed therein, and the content ofthe reinforced fibers may be lower in the first projection units than inthe base.

The base may include 10 to 30 phr (parts per hundred rubber) of thereinforced fibers based on 100 phr of a content of the first elasticbase.

The first elastic base may include at least one of an ethylene propylenediene monomer (EPDM), fluorine and silicone-based rubbers.

The first projection units may include a material including a secondelastic base, and the second elastic base may have a hardness that islower than the hardness of the first elastic base.

The reinforced fibers may include at least one of carbon fibers, glassfibers, and aramid fibers.

The width of the first projection units may be smaller than the fiberlength of the reinforced fibers.

The first projection units may include a material including a secondelastic base, and second projection units including the second elasticbase may be further provided on the first projection units.

The width of the second projection units may be smaller than the fiberlength of reinforced fibers, and the width of the first projection unitsmay be larger than the fiber length of the reinforced fibers.

A plurality of first projection units may be provided on the upper endof the base to be spaced apart from each other, and the plurality offirst projection units may form a closed loop on an upper side of thebase.

The plurality of first projection units may extend from an upper side ofthe base so that the arrangement lines of the first projection units areinclined at different angles.

The plurality of first projection units may extend so that arrangementlines of the first projection units are parallel to each other in azigzag arrangement or cross each other on the upper end of the base.

The plurality of first projection units may be provided to be spacedapart from each other on either of the upper end and a lower end of thebase, and the plurality of first projection units may form a closed loopon either of the upper and lower sides of the base.

The base may be positioned between an anode separator and a cathodeseparator along an edge of a cooling surface on which the anode and thecathode separators of the fuel cell are formed to face each other.

The base may be positioned on either side of upper and lower sides ofthe membrane electrode assembly along the edge of the membrane electrodeassembly to come into contact with the separator and the membraneelectrode assembly on respective sides thereof.

The base may be positioned along the edge of an end cell heater of thefuel cell stack, and may come into contact with the end cell heater atone side thereof and with the end plate of the fuel cell at a remainingside thereof.

To accomplish the above object, the present invention also provides amethod of molding a frame gasket for a fuel cell. The method includesmolding a base using a material including a first elastic base andreinforced fibers mixed therein, and molding first projection unitsusing a material, including a second elastic base, on an upper end ofthe base.

The merits of a frame gasket for a fuel cell according to an exemplaryembodiment of the present invention are as follows.

First, an elastomer may be directly molded without the application of aninsert (separator/gas diffusion layer/membrane electrode assembly/resinframe) to a mold, and reinforced fibers may be provided to reinforce themechanical rigidity of a flat elastomer base, thus improving the abilityof the gasket to maintain its shape.

Second, an insert, along with unnecessary processes, including a processof integrating the gasket and the insert, post-treatment of integratedmolded products, and washing of the insert, may be obviated,reducingprocessing costs and ensuring production cost savings.

Third, since the process of integrating with the insert is unnecessary,deformation or surface contamination of the separator during molding ofthe gasket may be fundamentally prevented, and the defect ratio ofmolding and the amounts of materials that are used may be reduced tothus ensure a cost savings effect.

Fourth, an adhesive must be applied on the surface of the insert tomaintain the shape of the gasket and to dispose the gasket at a desiredposition during the process of integrating the gasket, having poorrigidity, and the insert in the related art. However, in an exemplaryembodiment of the present invention, a costly adhesive is unnecessaryand the adhesive application process is not required, thus ensuring areduction of material and processing costs.

Fifth, the structural stability of the gasket may be improved using theflat elastomer base having high rigidity. The tolerance of other partsin the fuel cell may be accommodated and sealing of the fuel cell may beimproved due to projection units formed on the base.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are schematic views showing thesection of a frame gasket for a fuel cell according to an embodiment ofthe present invention;

FIG. 5 is an SEM image showing the fracture surface of the frame gasketfor the fuel cell according to the embodiment of the present invention;

FIG. 6, FIG. 7, and FIG. 8 are schematic plane views of the frame gasketfor the fuel cell according to the embodiment of the present invention;

FIG. 9 is a graph showing an increase in rigidity for each content ofthe reinforced fibers in the frame gasket for the fuel cell according tothe embodiment of the present invention; and

FIG. 10 is a graph showing a change in volume resistance, depending onthe type of reinforced fibers in the frame gasket for the fuel cellaccording to the embodiment of the present invention.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that the present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

As shown in FIG. 1, a frame gasket for a fuel cell according to anexemplary embodiment of the present invention includes a flat elasticbase 10, which is positioned along an edge of a separator, a membraneelectrode assembly, or an end plate to ensure sealing of the fuel cell,and which includes a first elastic base and reinforced fibers mixedtherein, and a first projection unit 20, which projects over the base 10and which includes an elastomer.

Various embodiments of various embodiments of the present inventionrelates to the frame gasket for sealing the parts of the fuel cell. Thebase 10 and the projection unit constituting the gasket may basicallyinclude elastomers. Examples used for the gasket are fluorine rubber(FKM), silicone rubber (VMQ), and isoprene rubber (IR). As shown in FIG.5, the present invention suggests EPDM rubber mixed with carbon fibersas a preferable embodiment, and this is because the EPDM rubber isinexpensive and may have excellent cold resistance and chemicalresistance compared to other elastomers.

Meanwhile, a first elastic base is provided as the elastomerconstituting the base 10 according to an exemplary embodiment of thepresent invention, and a second elastic base is provided as theelastomer constituting the projection unit. For convenience ofmanufacture, the base 10 and the projection unit may be formed using asame elastomer. Since the same elastomer is used, the base 10 and theprojection unit may be molded through a single step, and the materialcombination may be high even when the base and the projection unit aremolded through two steps. In addition, even though the first and thesecond elastic bases are the same and molding is performed through asingle step, the reinforced fibers are mixed only with the first elasticbase constituting the base 10, or the amount of the reinforced fibersmixed with the first elastic base is larger than that of the reinforcedfibers mixed with the second elastic base. Accordingly, a self-standingframe gasket for a fuel cell, which is the target of the presentinvention, can be sufficiently embodied.

On the other hand, when the first elastic base and the second elasticbase are different, it is preferable that the second elastic base,constituting the first projection unit 20 or a second projection unit30, as will be described later, have hardness which is lower than thatof the first elastic base. The hardness of the base 10 is increased todisturb pressing of the base due to the reinforced fibers, which areprovided to improve the structural stability of the gasket. However, asshown in FIGS. 1 to 4, the first projection unit 20 and the secondprojection unit 30 do not have flat surfaces, and the first projectionunit 20 and the second projection unit 30 include the elastomer havinglow hardness, so that the first projection unit and the secondprojection unit come into contact with parts constituting the stack toensure sealing, thereby minimizing the pressing force (clampping force)required during assembly of the cells. Accordingly, in an exemplaryembodiment of the present invention, the hardness of the second elasticbase is set to be lower than that of the first elastic base, thusensuring sufficient sealing of the frame gasket for the fuel cell.Moreover, the tolerance during assembly with other parts (gas diffusionlayer, membrane electrode assembly, or the like) constituting the stackmay be absorbed by the first projection unit 20 or the second projectionunit 30, which have low hardness, to thus improve the electrochemicalperformance uniformity of each part constituting the fuel cell.

However,even though the hardness of the first elastic base is higherthan that of the second elastic base, the first elastic base has apredetermined elasticity. Accordingly, since the gasket may be slightlybent due to the elasticity, the insert is added to a mold during moldingof the gasket. However, in an exemplary embodiment of the presentinvention, the base 10 of the gasket does not include only the firstelastic base, but includes the first elastic base and the reinforcedfibers mixed therein to thus increase the rigidity of the base 10,thereby overcoming the aforementioned problem.

Examples of the reinforced fibers mixed with the first elastic base mayinclude various types, but the present invention suggests carbon fibers,glass fibers, and aramid fibers as reinforced fibers useful forincreasing the rigidity of the base 10 of the gasket. However, the firstelastic base includes a hydrocarbon-based EPDM rubber in theaforementioned preferable embodiment. Therefore, among the reinforcedfibers, when the carbon fibers consisting mainly of carbon are used, theEPDM of the base 10 and the carbon fibers may be easily mixed without anadditional process for surface-treating the carbon fibers because theEPDM and the carbon fibers are both carbon-based materials. Accordingly,it is most preferable to use the carbon fibers in terms of costs and themanufacturing process.

As shown in FIG. 1, in the frame gasket for the fuel cell according toan exemplary embodiment of the present invention, the width of the firstprojection unit 20 is smaller than the fiber length of the reinforcedfibers A 11 regardless of the type of reinforced fibers that are used.The reason for this is that the frame gasket for the fuel cell accordingto an exemplary embodiment of the present invention is manufacturedusing injection or compression molding of the material, including thefirst elastic base and the reinforced fibers mixed therein, in the mold.That is, the reinforced fibers are partially oriented according to theflow of the base during molding in the mold, but when the fiber lengthof the reinforced fibers A 11 is smaller than the width of the firstprojection unit 20, the material, including the first elastic base andthe reinforced fibers A 11 mixed therein, may excessively flow into thefirst projection unit 20 regardless of a designer's intention.Accordingly, to prevent such excess flow, the width of the firstprojection unit 20 is set to be smaller than the fiber length of thereinforced fibers A 11. The fiber length of the reinforced fibers A 11may depend on the type of fibers, but the glass, aramid, and carbonfibers, which are suggested as representative examples in an exemplaryembodiment of the present invention, are 4 mm, 5 mm, and 3 or 6 mm inlength, respectively. The width of the first projection may depend onthe type of reinforced fibers that are used.

Portions of the constitution of FIG. 2 are the same as those of FIG. 1,and the first projection units 20 are positioned on either side of thebase 10 to face each other. Accordingly, the sealing of the fuel cellmay be improved compared to FIG. 1.

Portions of the constitution of FIG. 3 are the same as those of FIG. 1,and the second projection unit 30 including the second elastic base isfurther provided on the first projection unit 20. That is, the firstprojection unit 20 and the second projection unit 30 form the projectionunits. The width of the second projection unit 30 is smaller than thefiber length of reinforced fibers B 21, and the width of the firstprojection unit 20 is larger than the fiber length of the reinforcedfibers B 21.

Therefore, in FIG. 3, the reinforced fibers B 21 may move into the firstprojection unit 20 to increase the rigidity of the gasket. However,since the first projection unit has the same rigidity as the base 10,the second projection unit 30 needs to be further provided in order tomaintain the seal at the same level or higher.

Further, the projection unit may be provided in the manner of FIG. 4,and a recess unit 40 may be formed between the base 10 and the firstprojection unit 20 to prevent the reinforced fibers A 11 from movinginto the first projection unit 20. In this case, the width of the recessunit 40 is smaller than the width of the first projection unit 20 and issmaller than the fiber length of the reinforced fibers A 11, therebypreventing the reinforced fibers A 11 from excessively moving into thefirst projection unit 20.

The molding type of the gasket may be selected by a designer among theconstitutions of FIGS. 1 to 4, depending on the type of the reinforcedfibers used in the frame gasket for the fuel cell and the type ofcontact with each constitutional part of the cell.

A plurality of first projection units 20 may be formed on the base 10,regardless of the type of the constitutions of FIGS. 1 to 4.Specifically, as shown in FIG. 6, the plurality of first projectionunits 20 may be formed at predetermined standard intervals on one sideof the base 10 to be spaced apart from each other and to form a closedloop. Needless to say, to ensure that the entire base is sealed, thefirst projection units 20 are formed on the entire base 10 to form aclosed loop. However, in some cases, the first projection units 20 mayextend from a portion of the base 10, which is positioned on a manifold,forming a closed loop surrounding the manifold. In an exemplaryembodiment of the present invention, the sealing of the fuel cell may beimproved using the plurality of projection units.

Moreover, in an exemplary embodiment of the present invention, as shownin FIG. 7, the plurality of first projection units 20 may not bepositioned in a line, but may be positioned in a zigzag arrangement witha predetermined zigzag angle. Alternatively, as shown in FIG. 8, theplurality of first projection units 20 may be positioned to cross eachother and form a closed loop. For example, the first projection units 20may be positioned in a zigzag arrangement with different zigzag anglesto form a closed loop. The reason why the zigzag angles of the firstprojection units 20 are different from each other is that since theresistance to the flow of material, including the first elastic base andthe reinforced fibers A 11 mixed therein, is increased during molding ofthe gasket, the possibility that the material, including the firstelastic base and the reinforced fibers A 11 mixed therein, will moveinto the first projection unit 20 is reduced compared to thestraight-line arrangement of the first projection units 20. In addition,when the base 10 and the first projection units 20 are moldedsimultaneously through a single step, the content of the reinforcedfibers A 11 may be higher in the base 10 than in the first projectionunits due to the zigzag arrangement.

From the graph of FIG. 9, it can be confirmed that the rigidity of thegasket for the fuel cell, which is manufactured to have theaforementioned structure, is increased compared to that of aconventional gasket. FIG. 9 is a graph showing tensile strength as afunction of an elongation in the case where the first elastic base ofthe base 10 of the gasket includes the EPDM rubber and the carbon fiberswhich are added as the reinforced fibers. From FIG. 9, it can beconfirmed that when the carbon fibers are mixed in a content of 10 to 30phr, the rigidity of the frame gasket for the fuel cell is increasedcompared to the case where the carbon fibers are not included.Meanwhile, it can be seen that when the content of the carbon fibers is40 phr or more, mixing of the carbon fibers with the EPDM rubber becomespoor, thus reducing molding processability. Therefore, it is preferablefor the carbon fibers to be mixed in a content of approximately 10 to 30phr in terms of mixing of the carbon fibers with the EPDM rubber, anincrease in rigidity, the cost of products, and insulation resistance,as will be described later.

FIG. 10 is a graph obtained by measuring the volume resistance of thegasket sample to confirm the electric insulation of the gasket for thefuel cell according to an exemplary embodiment of the present invention(Before the description of FIG. 10, it is noted that the conventionaltechnology described in the graph of FIG. 10 means the volume resistanceof the gasket for the fuel cell, manufactured in advance by the presentapplicant, but does not mean a known technology). Unlike the gasket usedin other apparatuses, the gasket for use in the fuel cell comes intodirect contact with the membrane electrode assembly and the separator,which generate electricity and through which electric current flows, andaccordingly, electric insulation is considered as a very importantfactor. When the gasket is manufactured, the volume resistance relativeto electric insulation is very important. From the graph of FIG. 10, itcan be confirmed that when the aramid fibers or the glass fibers aremixed with EPDM, since the volume resistance is not largely reducedcompared to the conventional technology, the electric insulation of thegasket is insignificantly reduced, when the reinforced fibers are mixed.

When the carbon fibers are mixed, the volume resistance is reduced,unlike the gasket for the fuel cell which has been conventionally usedby the present applicant. However, since the volume resistance is 1×10⁹[Ω·cm] or more until the content of the reinforced fibers approaches 30phr, there is no problem in terms of electric insulation. Accordingly,the aforementioned reduction of the volume resistance is not consideredas a side effect. When carbon fibers that mix well with (i.e., arecompatible with) EPDM are used, there is a merit in terms of amanufacturing process. Accordingly, it is preferable to mix EPDM and thecarbon fibers though the volume resistance is reduced to a certainextent.

The base of the frame gasket for fuel cells according to an exemplaryembodiment of the present invention is positioned along an edge of theseparator, the membrane electrode assembly, or the end plate.Specifically, the base may be positioned along the edge of a coolingsurface, on which the anode separator and the cathode separator areformed to face each other, may be positioned along the edges of bothsides of the membrane electrode assembly so as to come into contact withthe separator at one side thereof and with the membrane electrodeassembly at the other side thereof, or may be positioned along the edgeof an end cell heater constituting the stack to come into contact withthe end cell heater at one side thereof and with the end plate at theother side thereof.

Further, a method of molding the frame gasket for the fuel cellaccording to an exemplary embodiment of the present invention mayinclude injection or compression molding the base 10 and the firstprojection units 20 or the second projection units 30 through a singlestep using the mold of the frame gasket for the fuel cell according toan exemplary embodiment of the present invention.

However, even if the width of the first projection unit 20 is controlledor the first projection unit 20 is positioned in the way suggested bythe present invention, a portion of the reinforced fibers (reinforcedfibers A 11 or reinforced fibers B 21) may move into the firstprojection unit 20 or the second projection unit 30. In addition, whenthe reinforced fibers move into the projection unit, the sealingstrength of the fuel cell may be reduced.

Therefore, the present invention suggests double injection orcompression molding processes to overcome the aforementioneddisadvantage. Specifically, the method may include a primary moldingstep of molding the base 10 using the material including the firstelastic base and the reinforced fibers mixed therein, and a secondarymolding step of molding the first projection units 20 on the base 10using the second elastic base.

As for the aforementioned frame gasket for the fuel cell, the base 10and the first projection units 20 are molded using different moldingprocesses. Accordingly, the projection units may not be disposed in acomplicated arrangement such as a zigzag arrangement, and the materialand the hardness of the projection unit may be made different from thoseof the base 10, thereby more easily accomplishing the object of thepresent invention.

For convenience in explanation and accurate definition in the appendedclaims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”,“upper”, “lower”, “upwards”, “downwards”, “front”, “rear”, “back”,“inside”, “outside”, “inwardly”, “outwardly”, “interior”, “exterior”,“inner”, “outer”, “forwards”, and “backwards” are used to describefeatures of the exemplary embodiments with reference to the positions ofsuch features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A frame gasket for a fuel cell, comprising: abase, which is positioned along an edge of a separator, a membraneelectrode assembly, or an end plate to extend from the edge of theseparator, the membrane electrode assembly, or the end plate to apredetermined width and height, and which includes a first elastic baseand reinforced fibers mixed therein to ensure sealing of a fuel cellstack; and a plurality of first projection units, which extend from anupper end of the base to project over the base and which include anelastomer, wherein a width of the plurality of the first projectionunits is smaller than a fiber length of the reinforced fibers to preventthe reinforcing fibers from being mixed into the first projection unitsduring manufacturing using injection or compression molding.
 2. Theframe gasket of claim 1, wherein the plurality of the first projectionunits extend from the upper end of the base, and the base and theplurality of the first projection units extend along the edge of theseparator, the membrane electrode assembly, or the end plate to form aclosed loop.
 3. The frame gasket of claim 1, wherein the plurality ofthe first projection units include a material including a second elasticbase.
 4. The frame gasket of claim 3, wherein the first elastic base isa same as the second elastic base, and the base and the plurality of thefirst projection units are integrally molded.
 5. The frame gasket ofclaim 1, wherein the plurality of the first projection units include amaterial including a second elastic base and the reinforced fibers mixedtherein, and a content of the reinforced fibers is lower in theplurality of the first projection units than in the base.
 6. The framegasket of claim 1, wherein the base includes 10 to 30 parts per hundredrubber (phr) of the reinforced fibers based on 100 phr of a content ofthe first elastic base.
 7. The frame gasket of claim 1, wherein thefirst elastic base includes at least one of an ethylene propylene dienemonomer (EPDM), fluorine and silicone-based rubbers.
 8. The frame gasketof claim 1, wherein the plurality of the first projection units includea material including a second elastic base, and the second elastic basehas a hardness that is lower than a hardness of the first elastic base.9. The frame gasket of claim 1, wherein the reinforced fibers include atleast one of carbon fibers, glass fibers, and aramid fibers.
 10. Theframe gasket of claim 1, wherein the plurality of the first projectionunits is provided on the upper end of the base to be spaced apart fromeach other, and the plurality of the first projection units form aclosed loop on an upper side of the base.
 11. The frame gasket of claim10, wherein the plurality of the first projection units extend from anupper side of the base so that arrangement lines of the plurality of thefirst projection units are inclined at different angles.
 12. The framegasket of claim 10, wherein the plurality of the first projection unitsextend so that arrangement lines of the plurality of the firstprojection units are parallel to each other in a zigzag arrangement orcross each other on the upper end of the base.
 13. The frame gasket ofclaim 1, wherein the plurality of the first projection units is providedto be spaced apart from each other on either of the upper end and alower end of the base, and the plurality of the first projection unitsforms a closed loop on either of upper and lower sides of the base. 14.A method of molding the frame gasket for the fuel cell of claim 1, themethod comprising: molding the base using a material including the firstelastic base and the reinforced fibers mixed therein; and molding aplurality of the first projection units using a material, including asecond elastic base, on the upper end of the base.